ABSTRACT
The major changes that are needed will be difficult—some will say impossible--to achieve by traditional approaches. By the close of the century, the world may have to feed as many as two billion additional people, mostly living in the tropics and largely on marginal lands. To provide a minimally acceptable food supply for their people by the year 2000, developing countries will have to double their own food production. Furthermore, food exports from food surplus nations need to be tripled, according to the 1980 Brandt Commission Report. Augmenting global carrying capacity by the use of energy and by conversion of marginal lands already brings diminishing returns in agriculture, and is unsustainable to the extent that nonrenewable resources are wasted and renewable ones are degraded or destroyed. The world faces the transition from cheap but exhaustible resources, like petroleum, to currently expensive but renewable resources, like solar, biomass energy, and hydroelectricity.
